There has been known a foil bearing as a bearing which is less liable to cause a whirl and enables management of a gap width of a bearing gap to be performed easily even under an environment in which a temperature change is large. The foil bearing has a bearing surface formed of flexible metal thin plates (foils) having a low rigidity with respect to bending, and is configured to support a load by allowing flexure of the bearing surface. Such a configuration of the foil bearing enables automatic adjustment of a bearing gap to an appropriate width in accordance with, for example, an operation condition. For example, in Patent Literature 1 described below, there is disclosed a foil bearing of a so-called bump type as an example of a radial foil bearing configured to support a radial load.